The friction material in wet-type friction clutches generally operates in an oil submerged environment and is often paper-based material used to form friction material rings. To reduce waste during manufacture, the wet friction material ring may be stamped out in segments and then bonded to the plate to form the friction material rings. However, the edges between the segments can cause premature material failure and reduce the life of the wet friction material. One reason for premature material failure is due in part to the ability of fluid to enter the uncompressed edge of the cut joint.
U.S. Pat. No. 6,585,096 describes a joint with reduced thickness and U.S. Pat. No. 7,165,664 has a depressed flat area at the joint.